1920.] E. Ghosh : Anatomy of the Solenidae. 63 



interlamellar tissue only leaving spaces inside the plications. The 

 plicae are connected with one another by interplicar tissues and 

 the surface of the gills is covered over by a thin membrane. 



The oesophagus is horizontal and short. Cardiac stomach 

 extending slightly in front beyond the oesophageal portion. 

 Pyloric stomach not protruding posteriorly beyond the origin of 

 the coecum. Coecurn of the crystalline style short and tapering 

 at the distal extremity. The anterior limb of the intestine form- 

 ing a few closely placed coils near the junction with the posterior 

 limb which is simple and presents a wide loop above before it 

 ends in the rectum. 



Genus Pharella, Gray, 



1854. Pharella, Gray, Ann. Mag. Nat. Hist. (2) XIV, p. 24. 

 1858. Pharella, Gray, Adams, Gen. Recent Moll., II, p. 343. 

 1887. Pharella, Gray, Fischer, Mayi. Conch., p. 1108. 



The animal of a single species of Pharella (P. orientalis, Dun- 

 ker) 1 is known through the researches of Bloomer (10). The fol- 

 lowing diagnosis is drawn from his paper : — 



Animal. Body somewhat elongated. Pedal aperture extend- 

 ing over the anterior adductor muscle dorsally and along the ventral 

 margin still further posteriorly. No fourth aperture. Siphons 

 separate, consisting of short anal and branchial tubes, fringed with 

 tentacles. Anterior adductor muscle large and nearly rounded. 

 Posterior adductor muscle large and rounded. Foot large, com- 

 pressed and abruptly truncate in front. Retractor pedis anterior 

 muscle not bifurcated ; its fibres passing inside the longitudinal 

 muscles of the foot. Retractor pedis posterior muscle connected 

 with the posterior adductor muscle. Labial palps short, wide and 

 angular. Anterior lip separated from the anterior adductor muscle 

 by a short interval. Gills elongated, narrow, heterorhabdic and 

 plicate. Coecum of the crystalline style directed forward from 

 the ventral aspect of the pylorus. Intestine of two simple limbs. 

 A single nerve from each cerebro-pleural ganglion. Viscero- 

 parietal gangha under the posterior adductor muscle, each giving 

 off a branchial and a pallial nerve. Heart towards the anterior 

 end of the pericardial chamber. 



The anatomical features of the present animal distinctly show 

 that it is elongated in the middle region of the body between the 

 two adductor muscles. Allowing for the necessary changes con- 

 sequent upon this elongation, this genus is related to CuUellus 

 which seems to be more primitive than the present one in many 

 respects. 



Genus Siliqua, Miihlfeldt, 



181 1. SiUqua, Muh\MA\., Magazin d. Ges. naturf. Fr. Berlin, W (^i), 



P- 38. 

 1817. Leguminaria, Schumacher, Essai Nouv. Syst. Habit, des Vers 

 Testace, pp. 42, 126, pi. vii, fig. i. 



I Solen orientalis, Dunker, Proc. Zool. Soc. Land., p. 423 (1861). Cultel- 

 I'ls orientalis, Clessin in Martini-Chemnitz, Conch. Cab., XI, p. 46, 



